This application relates to magnetic disc drives and more particularly to an improved disc drive assembly including a shroud feature and method of attaching the shroud feature.
Disc drives are data storage devices that store digital data in magnetic form on a storage medium on a rotating information storage disc. Modern disc drives include one or more rigid discs that are coated with a magnetizable medium and mounted on the hub of a spindle motor for rotation at a constant high speed. Information is stored on the discs in a plurality of concentric circular tracks typically by an array of transducers (xe2x80x9cheadsxe2x80x9d) mounted to a radial actuator for movement of the heads relative to the discs. Each of the concentric tracks is generally divided intro a plurality of separately addressable data sectors. The read/write transducer, e.g., a magneto resistive read/write head, is used to transfer data between a desired track and an external environment. During a write operation, data is written onto the disc track and during a read operation the head senses the data previously written on the disc track and transfers the information to the external environment. Critical to both of these operations is the accurate locating of the head over the center of the desired track.
The heads are mounted via flexures at the ends of a plurality of actuator arms that project radially outward from the actuator body. The actuator body pivots about a shaft mounted to the disc drive housing at a position closely adjacent the outer extreme of the discs. The pivot shaft is parallel with the axis of rotation of the spindle motor and the discs, so that the heads move in a plane parallel with the surfaces of the discs. The radial position of the heads is controlled through the use of a voice coil motor (VCM) assembly positioned adjacent to the disc.
The rotation of the disc at high speeds during operation creates airflow adjacent the disc surfaces. When a large volume of air space is adjacent the rotating disc, this airflow is often turbulent. It is preferable that turbulence in the airflow be minimized. Turbulence can effect the radial and vertical positioning of the head over the center of the desired track, and can cause the disc to flutter undesirably.
To reduce the amount of turbulent airflow during operation of the disc, often an inner disc shroud is constructed in the base plate of the disc drive and by structural features on the base plate to define a minimal disc operation space. The shroud surrounds the disc such that the inner surface of the shroud is in close proximity to the outer peripheral surface of the disc around its circumference to reduce turbulence. It is preferable that the disc shroud enclose as much of the circumference of the outer peripheral surface of the disc as possible, without interfering with other components of the disc drive. However, it is often difficult to construct a base plate or structural features on the base plate that enclose as much of the circumference of the outer peripheral surface of the disc as possible while allowing for proper installation and operational clearances for the operational components in the disc drive. For example, a portion of the disc circumference is often left unshrouded for installation of the actuator. Additionally, openings in such a disc shroud are typically provided adjacent the actuator assembly to accommodate the voice coil motor (VCM), accommodate movement of the actuator and allow for proper installation and operational clearances for these components. These openings or gaps in the shroud, however, permit turbulence to develop when the disc is rotated.
Against this backdrop the present invention has been developed. The invention relates to a shroud feature and method for incorporating an airflow shroud feature in a disc drive assembly. The airflow shroud feature of the present invention is connected to the cover of the disc drive rather than the base plate. When the disc drive cover incorporating the shroud feature is placed on the disc drive, the shroud feature surrounds at least a portion of the circumference of the outer peripheral surface of the disc to reduce turbulence when the disc is operated.
In one preferred embodiment, the invention includes a disc drive having a base plate, and an information storage disc supported for rotation by a drive motor on, the base plate. The disc drive also has a top cover having a shroud rigidly connected to the top cover by engagement of the shroud with a feature of the top cover. The shroud operably directs air-flow along the peripheral edge of the disc during drive operation when the cover is installed on the base plate.
The invention can be implemented in accordance with another preferred embodiment as a cover for a disc drive. The cover includes a generally planar body shaped to cover a disc and an actuator assembly when mounted on the base plate, and a disc shroud connected to an underside surface of the generally planar body by engaging a feature on the generally planar body. The disc shroud extends from the underside of the generally planar body and around a portion of the disc when the cover is installed onto the base plate.
The invention can be implemented in accordance with another preferred embodiment as a method of connecting a disc shroud to a top cover of a disc drive. The method includes the steps of providing a feature in the top cover of the disc drive; and engaging a portion of the shroud with the feature in the top cover to connect the shroud to the cover in a position such that when the top cover is placed on a base plate of the disc drive, the shroud is positioned adjacent the outer peripheral edge of a disc. The shroud directs air-flow along the peripheral edge of the disc during drive operation.